Biometric sensors are widely used to distinguish between (a) individuals that are authorized to engage in an activity, and (b) individuals that are not authorized to engage in that activity. For example, fingerprint sensors are commonly used to determine whether a fingerprint provided by an individual matches information in a database, and if a match is determined, then the individual may be allowed to engage in an activity. For example, the individual may be allowed to enter a building or room, or allowed to use an electronic device (such as a cell phone).
Biometric sensors can be deceived (a.k.a. “spoofed”), and thereby permit an unauthorized individual to engage in an activity that is reserved for authorized individuals. Spoofing a fingerprint sensor may be accomplished in many different ways. These include: using a fake fingerprint, and using a dead finger from a person. One method of guarding against spoofing involves determining whether the biometric exhibits characteristics associated with liveness.
As more and more biometrics are used for user identification and/or verification, liveness detection becomes increasingly important in order to ensure security and accuracy. Liveness detection is important because many methods of deceiving an identification system and/or verification system use spoofs that are not alive. For example, latex may be made to have ridges and valleys resembling a fingerprint of an authorized user. When such a latex spoof is presented to a fingerprint scanner, the scanning system may falsely conclude that the latex spoof is the finger of an authorized user, even though the latex spoof is not part of a living being. Therefore, a system which is able to detect whether a biometric is alive would be useful in detecting the presence of a spoof. In such a system, if a determination is made that a biometric was not alive, then the individual presenting the biometric would be denied the requested activity even if the biometric matches information in the identification/verification database.